1. Field of the Invention
The present invention relates to a tablet for producing a one-sided sealing-type semiconductor device, comprising an epoxy resin composition with suppression in the generation of bowing and high reliability, a wafer with a resin layer and a semiconductor device produced by using the tablet.
2. Discussion of the Related Art
Conventionally, a cured resin layer is formed on one side of a wafer comprising a plural projected electrodes by subjecting a tablet comprising an epoxy resin composition to hot press molding, wherein the epoxy resin composition is obtained by cold pressing molding. However, in the wafer with a resin layer in which a cured resin layer is formed by using the tablet described above, there arises a problem that bowing is generated. Specifically, when a cured resin layer is formed by using the above-mentioned tablet, the bowing of the wafer with a resin layer is undesirably caused because the physical properties such as a coefficient of linear expansion of a cured product of an epoxy resin composition, which is the cured resin layer, are different from those of a wafer. The wafer with a resin layer in which the bowing described above is generated causes troubles during conveying and dicing, and has a defect that its applicability to the substrate becomes poor. Further, there also arise some problems that a stress is generated at the interface of the wafer and the cured resin layer, so that its reliability is impaired.
In addition, in the technique of packaging (sealing) a semiconductor element in the field of semiconductor devices in the recent years, one-sided sealing-type semiconductor devices, for instance, have been remarked and actually used. A semiconductor device in which a semiconductor element is sealed by a cured product of an epoxy resin composition has excellent mass-producibility and low costs. Further, the above-mentioned one-sided sealing type semiconductor device can have high performance by highly integrating the semiconductor element. In addition, in a method of mounting a semiconductor element to a board, which is the insulating substrate mentioned above in a flip chip manner or a direct chip attachment manner, sealing is usually carried out by one-sided sealing in a state of incorporating the semiconductor element, or alternatively by filling a molten thermosetting resin composition in a void between the insulating substrate and the semiconductor device and curing the composition. However, these semiconductor devices have some problems of generation of bowing of the package caused by curing shrinkage of a sealing resin, and incongruence in the coefficients of linear expansion of the insulating substrate and the sealing resin (cured product). In the semiconductor device in which the bowing described above is generated, peeling or the like is caused at the sealing interface by the stress due to bowing, so that its reliability is lowered, thereby resulting in poor applicability to a substrate. Therefore, a solution to such a problem is desired.
An object of the present invention to provide a tablet comprising an epoxy resin composition for producing a one-sided sealing-type semiconductor device with suppression in the generation of bowing and high reliability.
Another object of the present invention is to provide a wafer and a semiconductor device produced by using a tablet comprising an epoxy resin composition, and processes for producing the tablet and the wafer.
Still another object of the present invention is to provide a method of preventing generation of bowing of the wafer and the semiconductor device.
Still another object of the present invention is to provide a use of a tablet comprising an epoxy resin composition for preventing generation of bowing of the wafer and the semiconductor device.
These and other objects of the present invention will be apparent from the following description.